Clashes have erupted in two cities in northern Egypt, and protesters rallied in Cairo in the latest demonstrations against Egypt's President Mohammed Morsi, who claims the recent wave of anti-government unrest is the work of conspirators.

In the Mediterranean city of Alexandria on Friday, hundreds of unidentified assailants threw stones and fire bombs at protesters rallying against Morsi and the Muslim Brotherhood, Egypt's most powerful political group.

The anti-government protesters hurled stones back at the assailants during the clash in a square that used to be home to the Brotherhood's office before it was stormed weeks ago by demonstrators.

Morsi's opponents say the elected president has continuously defied legal norms to force through his agenda and trampled on the judiciary's independence in a bid to consolidate his power.

They also say he has failed to live up to his promises to have an inclusive political process where liberals are represented.

Separately, protesters and riot police clashed in the president's home province of Sharqiya in the Nile River Delta.

Police fired tear gas and exchanged stones with demonstrators who tried to torch a Brotherhood office in the city of Zagazig, 50 miles north of the capital, Cairo.

Beating of drums

In Cairo, hundreds of Egyptian protesters rallied in front of the office of the nation's embattled Prosecutor General Talaat Abdullah, part of a nationwide call to hold demonstrations against actions that Morsi has taken against the opposition.

The protesters, clapping and beating drums, sealed off Abdullah's office with locks and chains and displayed a sign that read: "Leave. Enough."

"We are here to say that we are not fearful, we are not hiding," said Wageh Abdel-Salam, one of the demonstrators.

"The revolution must continue."

On Monday, Egypt's prosecutor general issued arrest warrants for five of Egypt's most prominent democracy advocates and activists over allegations that they instigated violence last week near the Brotherhood's headquarters in Cairo.

Nearly 200 people were injured in those violent clashes, which were among the worst in three months between anti-government protesters and supporters of the Brotherhood.

In Washington, State Department spokeswoman Victoria Nuland expressed concern with the reports of arrest warrants for Egyptian political activists and the lack of information provided by Egyptian authorities.

"This case is being investigated while other cases, including cases where demonstrators were attacked outside of the presidential palace in December or where there were cases of extreme police brutality, have not been appropriately investigated," she told reporters.

The violence was rooted in an incident a week earlier when members of the Brotherhood slapped a woman to the ground and beat up other activists who were spray-painting graffiti against the group outside its headquarters in an eastern district of Cairo.

Earlier this week, Morsi responded with speeches harshly criticizing his opponents and calling them thugs paid to derail democracy.

"No one in our neighborhood wants this nation to stand on its feet. I will cut off any finger that meddles in Egypt," Morsi said, alluding to foreign interference in Egypt from other nations he did not identify.

"I can see two or three fingers that are meddling inside."

"There is an enemy outside Egypt and there is a devil inside that is maliciously messing with people's minds," Morsi told Egyptian expatriates in Qatar on Tuesday where he was attending an Arab League summit.